How to share a recorded sound on iOS?

[matthias_livecode_150811 at m-r-d.de]

> 
> Seems Messages does not support the .caf file type.
> 

I have to correct this.
Sending files to iMessage app through the sharing feature is not possible for all apps, even if they are from Apple. Tried here for example with the File.app from Apple on the iPhone. iMessage is not offered as targed in the share sheet.